Downing Street said the Chief Medical Officer for England, Dame Sally Davies, still regarded the risk to the UK as "low".

Chief executive of Public Health England Duncan Selbie described the challenge of introducing screening at Heathrow as "phenomenal".

In a weekly message to staff, he said that once the existing measures covering Heathrow, Gatwick and the Eurostar terminal at St Pancras had "settled", they would be rolled out to other ports of entry.

"Please be assured that we are thinking hard and listening carefully to those on the ground to see how we can make this more sustainable," he said.

"What I am certain of is that we have the people who know how to keep the country safe and that is exactly what we will do."

On Friday, a senior Doctors Without Borders official said recent pledges of help and deployments to Africa's Ebola-hit regions have had no impact on the epidemic.

It follows the launch of another urgent appeal for funds by the UN to help fight the virus after a $1bn trust fund which opened last month received just $100,000 (£62,000).

Conservative MP Sir Roger Gale has called for the screening regime to be extended to ferry passengers arriving at the port of Dover.